/*
 * Copyright (c) 2014 pkzd/1.0, 颜文泽(robin)
 * All rights reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     1 Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     2 Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include	"fs.h"
#include	<fcntl.h>
#include	<stdio.h>
#include	<errno.h>
#include	<string.h>
#include	<unistd.h>
#include	<stdlib.h>

static int cat(char *device, char *pathname);

int
main(int argc, char *argv[])
{
        if(argc < 3){
                fprintf(stderr, "Usage: ./cat device pathname\n");
                exit(1);
        }
	return cat(argv[1], argv[2]);
}

static int
cat(char *device, char *pathname)
{
	int fd;
	int ino;
	int i, j;
	char buf[BLKSIZ];
	struct filsys spb;
	struct inode inode;

	if((fd = open(device, O_RDWR)) == -1){
		fprintf(stderr, "Error: cannot open device %s: %s\n", device, strerror(errno));
		return -1;
	}
	if(bread(fd, NRSVSCT, &spb, 1)){
		close(fd);
                fprintf(stderr, "Error: cannot read superblock of %s\n", device);
                return -1;
	}
	if(spb.s_magic != FS_MAGIC){
		close(fd);
		fprintf(stderr, "Error: unknow file system of %s\n", device); 
		return -1;
	}
	if(!(ino = namei(fd, &spb, pathname, 0, 0))){
		close(fd);
		fprintf(stderr, "Error: cannot findfile %s\n", pathname);
		return -1;
	}
	if(iread(fd, &spb, ino, &inode)){
		close(fd);
		fprintf(stderr, "Error: cannot read file %s\n", pathname);
		return -1;
	}
	for(i = 0, j = inode.i_size / BLKSIZ; i <= j; i++){
		if(!log_read(fd, &spb, i, buf, &inode, 1)){
			close(fd);
			return -1;
		}
		write(STDOUT_FILENO, buf, i != j ? BLKSIZ : inode.i_size % BLKSIZ);
	}
	return close(fd);
}
